The Bullet Ant's Sting Packs a Painful Punch

Bullet ants live in tropical rainforests of Central and South America, and are unique in that they nest in the ground in colonies of around 3,000 individuals — absolutely enormous numbers, by ant standards. Because their cities are so large, they are prime targets for large predators that know that a humongous ant mound is chock full of nutritious larvae, pupae and adults concentrated in one place. In addition to the risks at home in the ant nest, the individual ants forage mainly in the forest canopy where they face squadrons of predatory birds, lizards, frogs, monkeys and other insects and spiders.

According to Schmidt, because they're very large and busy insects that are not camouflaged to avoid predators, individual bullet ants are conspicuous as they scurry around in the trees. However, unlike many insects that can fly or jump away when attacked, bullet ants have to either hold their ground or take the risky action of bailing out of the tree and falling sometimes dozens of meters to the ground. As a result, for the bullet ant, the best strategy for their lifestyle is to possess extremely painful and toxic stings.

However, the bullet ant doesn't prefer to sting if it could just be left alone.

"Bullet ants have several types of warning defenses that they use to alert potential predators not to risk attempting to eat them," says Schmidt, in an email. "They can stridulate, which to us sounds like a rhythmic little squeak, and is a typical warning sound that has a broad frequency spectrum and simple structure, much like the warning rattle of a rattlesnake. Bullet ants also have the olfactory warning of smelling somewhat like burnt garlic to alert a predator that they are not tasty and worth the risk of attacking. Finally, bullet ants visually warn by being shiny black and advertising that if you attack you will find yourself on the losing end of the situation."

Although the painful sting of a bullet ant is scalding, throbbing and unabating for up to 24 hours after contact, they're not particularly dangerous.

"One of the advantages of social insects is that they can attack en masse to defend their colony," says Schmidt. "In the case of a person who does not heed the painful warning and keeps attacking a bullet ant colony, 245 stings could kill a 154-pound (70-kilogram) healthy person. I am aware of no cases of death from bullet ant stings."

Some ceremonial manhood rituals, like those practiced by the ​​Satere-Mawe of the Amazon region of Brazil, involve participants being stung a few dozen times and no deaths have evver been reported.

"That is not to say that the venom is not highly lethal, as only a few stings would be required to kill a small mammal such as an attacking rodent or insectivore," says Schmidt.

Schmidt, who has been stung by just about every insect under the sun, says they're intensely painful, but in their own, special way.

"Bullet ant stings differ from other ant, wasp or bee stings in that they cause intense pain lasting anywhere from 12 to 36 hours," he says. "In contrast, a tarantula hawk wasp sting is painful for only a few minutes and the honeybee sting intensely hurts for only five to 10 minutes."

According to Schmidt, bullet ant venom is composed mainly of poneratoxin, a small peptide of 25 amino acids. This neurotoxin's main function in the body of vertebrate animals like us is to stimulate the receptors in the body that cause intense pain.

"Unlike many other insect pain-inducing proteins or peptides, poneratoxin sticks to the pain receptors for a long time and is difficult to deactivate — thus the long-term pain," says Schmidt.